Field
The present disclosure relates generally to analog-to-digital converters (ADCs) and including excess loop delay compensation in sigma-delta ADCs.
Related Art
Sigma-delta modulation is a method for encoding an analog input signal into a digital output signal. A sigma-delta analog-to-digital converter (ADC) encodes the analog input signal using a high-frequency sigma-delta modulation, and then filters the encoded input signal to form a higher-resolution but lower sample-frequency digital output. The first step in a sigma-delta modulation is delta modulation of the analog input signal. In delta modulation, a change in the analog input signal, namely a delta, is encoded to provide the digital output signal. The accuracy of the delta modulation is improved by passing the digital output signal through a digital-to-analog converter (DAC) and combining the resulting analog signal, namely the sigma, to the analog input signal forming a feedback loop with forward gain to reduce errors introduced by the coarse sub-ADC.